ASTR 451 Stellar Astrophysics

ASTR 451 Stellar Astrophysics

Course Syllabus
Fall 2016

Instructor: Dr. Patrick Hartigan, Hermann Brown 350, Phone: X2245
Time: MWF 11:00 am - 11:50 am
Room: HBH 254
Office Hours: After class on M and F, and by appt.

Outline of Course: The course material is split roughly evenly between stellar interiors and stellar atmospheres, and is taught at a level that is fairly standard across first-year graduate/advanced senior astrophysics curricula in the US. Stellar Astrophysics is one of the group of nine `core' classes from which Ph.D. students in the Physics and Astronomy Department at Rice must choose at least four. The course is intended for first-year graduate students and for advanced Rice undergraduates who have already taken ASTR 350 (Introduction to Astrophysics - Stars). While there are no specific astrophysics prerequisites for graduate students, those without any previous training in astrophysics may find they need to fill in some basic background material outside of class. At times in the past this course was co-listed as ASTR 551.

Text(s): The subject of modern stellar structure dates back nearly a century, and there are many textbooks that have been written on the subject. Some books cover only stellar atmospheres, others only stellar interiors. Because Rice offers a separate course on compact objects, I felt that something like half of ASTR 451 should be stellar atmospheres, with the treatment of white dwarfs, neutron stars, and black holes brief. Reliance on computer programs varies widely between texts, as does the relative emphasis placed on nuclear processes, radiative transfer, oscillations, line formation and so on.

A good balance between all of these in my opinion is a book by George W. Collins II entitled The Fundamentals of Stellar Astrophysics. This book is rather theoretical in nature, and some students have found it difficult to read, though I've found in the years after they take the class most students are glad to have had it as a textbook and reference. It was published in 1989 by W.H. Freeman and Co. with ISBN 0-7167-1993-2 (QB801.C615). Unfortunately, the book is out of print, but is available for free on-line at I encourage you to purchase a copy of this book if you can find it, or at least print out and bind the web PDF files.

For the stellar atmosphere portion of the course, Collins has a fairly complete theoretical description, but for our class we will also want a strong connection to the observations. Fortunately, Gray has updated his text entitled The Observation and Analysis of Stellar Photospheres, and we will base most of the atmospheres lectures on this text and on Collins.

I looked into several other texts for this class, and list them below, roughly in order of my preference, along with my personal view. I hope you find them useful as references. In terms of level, the Collins book falls in the middle of the graduate texts somewhere.

Undergraduate Texts:
   Carroll and Ostlie Introduction to Astrophysics  (1999) -- A thorough
   undergraduate text with excellent introductory sections on stellar evolution and
   stellar atmospheres. If you know all this well you will be fully ready for our class.
   A very good reference for your review.
   Shu The Physical Universe (1982) -- Contains an interesting discussion
   of fusion from the standpoint of particle physics, and a brief discussion of stellar
   Zeilik and Gregory  Introductory Astronomy and Astrophysics (1998) --
   A brief introduction to the field with an emphasis on observations.
   Bohm-Vitense Stellar Astrophysics v1: Basic Stellar Observations and Data (1989)
   Bohm-Vitense Stellar Astrophysics v2: Stellar Atmospheres (1989)
   Bohm-Vitense Stellar Astrophysics v3: Stellar Structure (1989) -- Short 
   texts on the subjects with an emphasis on observations, and written at a somewhat lower
   level than the graduate texts.

Other Graduate Texts:
   Rose Advanced Stellar Astrophysics (1998) A somewhat more advanced text
   than Collins, with more focus on compact objects and less on atmospheres. If we did not
   have a compact objects course we would probably use this text for that subject here.
   The general relativity section I thought was especially good. Collins has a more
   logical organization overall.
   Clayton Principles of Stellar Evolution and Nucleosynthesis (1983) --
   Still the standard reference for anything related to nucleosynthesis.
   Novotny Introduction to Stellar Atmospheres and Interiors (1973) --
   Has very clear expositions of stellar interiors and atmospheres, laid out in a logical
   straightforward progression, and includes descriptions of some basic codes.
   Needs a more modern version.
   Bowers and Deeming Astrophysics v1: Stars (1984) -- A standard textbook
   on stellar structure with useful insights; some users have complained about typos.
   Hansen and Kawaler Stellar Interiors (2004) -- Some very nice sections on
   oscillations. I used this text in previous classes but found the organization to be too
   chaotic, and the explanations not as clear as they could be.
   Mihalas Stellar Atmospheres (1978) -- A highly theoretical book on
   all aspects of stellar atmospheres. This text goes into more detail than we desire
   for this class. A good reference if you end up doing this for your research.
   Kippenhahn and Weigert Stellar Structure and Evolution (1991) -- Has a
   following among some astronomers, but I find the writing style to be unclear and the 
   book to be difficult to read. It focuses on a series of specific aspects of stellar structure.
   Part of the A&A series of textbooks from Europe.

Classic Texts
   Schwarzchild Structure and Evolution of Stars (1958)
   Chandrasekhar Radiative Transfer (1950)
   Eddington Internal Constitution of the Stars (1922)

Internet Disturbances: Please turn off all ringing, beeping devices and do not surf the internet, text, update Facebook, take selfies, email, chat, or use any other electronic diversion during class. If you must do anything like that, take it outside.

Grading: Based on problems (25%), presentations (10%), preparation (5%), two short oral exams (20% each), and a final exam (20%). Here is the grade distribution from the three previous times I have taught the couse. Many students find the material to be challenging and have to put in more effort than they do for most other graduate classes to obtain a given grade, and students should expect that going into the class. The subject material is satisfying, but it is not easy.

Absence and Late Policies: There are no specific requirements regarding class attendance on lecture days. However, I don't think I've ever seen a student do well in this class without regular attendance. The material is complex and difficult to learn from a book. Students must attend on presentation days and must be on time for all oral exams. There are no makeups for these except for doctor-verified illnesses. If students know beforehand they will not be avilable for presentations or exams they should contact me ASAP so hopefully we may reschedule for the entire class. Homeworks must be turned in on time to receive full credit.

Honor Code: A general description of the honor code is avilable on-line.
EXAMS: Once students have taken an oral exam they cannot discuss the contents of the exam until all students in the class have taken the test.
PROBLEMS: Problems are an important component to this class, and I will assign them in problem sets, probably 3 or 4 such sets throughout the semester. We may not have time to cover all the solutions in class, so if necessary we may meet at some other time to discuss problems. The honor code applies to the problems in the following way. If the student cannot solve a problem in an hour, the student can keep working on it alone or ask for hints from a classmate who has done the problem. After writing up the problem, students should describe the level of help they required in doing it. Students should turn in their own work and analysis on the homework sets, but may discuss the general nature of the problems with one-another.

Auditors: Should attend class, but can do problems and presentations or not as they wish.


Lectures: For the stellar interiors half, we will follow the Collins book for the most part, though I will augment material as appropriate. For the stellar atmospheres part we will again obtain the theoretical framework from Collins, but will connect with the observations using Gray's book. There are some nice web movies about time evolution of stellar interiors that we will also spend some time studying. Students should read, and think about the material before coming to class. Because we will be using the Collins text as a basis for some of the lectures, students should download the appropriate chapter from the web and print it out prior to coming to class.

Presentations: In-class presentations will be based on recent (typically within 10 years) journal articles that relate to stellar atmospheres or interiors. The choice of the article is up to the student, but I must approve the article beforehand. The presentations should be about 25 minutes long (depending on class size), and are informal. There is no need to make a fancy powerpoint presentation like you might do for a seminar talk. However, it is important for students to understand all the basic physics as it relates to the paper. Students should introduce the subject clearly and identify where the paper uses what we are studying. This is one way for students to get some practice teaching. Presenters must provide classmates and professor with hardcopies of the article they will discuss well in advance of the presentation. Each student will do one presentation on stellar atmospheres and one on stellar interiors during the semester. Unless enrollment is large, we should be able to fit them all in.

Short (30-50 minute) Oral Exams: Previous students have commented upon completion of the class that they would have preferred more frequent tests of their knowledge to help keep them from getting too far behind. Cramming large amount of material for the final usually does not work well, and although problem sets help in this regard, they differ significantly from the final in that they are longer, more collaborative, and more complex computationally.

In response to that feedback, I now conduct individual oral exams in my office, where the exams cover basic material we studied in class. Although sometimes painful, all graduate students (and undergrads who aspire to graduate work) need to learn how to handle oral exam situations without panicking or freezing up, because that is how qualifying exams are done, and, eventually, what job interviews are like. There really is no better way to find out what someone knows than to see what they write on the board. Material on the exams is pledged in the sense that no one may discuss the contents of the exams or provide any hints as to what to study until all class members have taken it. Scheduling the exams will be something we will figure out as the semester progresses. Right now I have exams scheduled in lieu of class on some Fridays, but if we run short of time we may need to schedule exams in addition to classtime. At the risk of stating the obvious, no aids of any kind are allowed during the oral exams.

Final: The final will be either closed book and closed notes, and will cover the entire term, or will be a short oral that focuses more on the last third of the class. We'll decide as we move forward which of the two is a better option for the class.


The following is a target schedule for the semester. Notice that there are two presentation days, time TBD. In the unlikely event that we are ahead of schedule we can hold these during classtime. Otherwise we will need to find another day.

	DATE               TOPIC                                          CHAPTER
       ------------- Introduction, Physics Overview -------------------

       M 8/22        Orientation Meeting/Astronomical Terminology        BV,G1-4
       W 8/24        Astronomical Observations of Stars                  BV,G1-4
       F 8/26        Phase Space, Statistical Equilibrium                C1, R3

       M 8/29        Boltzmann Transport Equations, Fluids and Tensors   C1, R3
       W 8/31        Fluids, Ideal and Degenerate Equations of State     C1, R3
       F 9/2         Eqns of State, Timescales for Stellar Phenomena     C3

       -------------- Stellar Interiors and Evolution ------------------

       M 9/5         **** NO CLASS (Labor Day) ****
       W 9/7         Equations for Stellar Interiors                     C2
       F 9/9         Equations for Stellar Interiors                     C2

       M 9/12        Polytropic Equations and Variables                  C2
       W 9/14        Polytropic Solutions                                C2
       F 9/16        Gravitational Energy, Nuclear Reactions             C3, R6

       M 9/19        Nuclear Reactions                                   C3, R6
       W 9/21        Nuclear Reactions, Radiative Transfer               C3, C4, R6
       F 9/23        Radiative Transfer                                  C4

       M 9/26        Radiative Transfer, Opacity, Convection, Conduction C4
       W 9/28        Stellar Evolution: Protostars                       C5
       F 9/30          **** ORAL EXAM #1 ****

       M 10/3        Stellar Evolution: Main Sequence                    C5
       W 10/5        Stellar Evolution: Giants and Supergiants           C5
       F 10/7        Stellar Evolution: Supernovae, Compact Objects      Web Movies, C6, R12

       M 10/10       **** NO CLASS (Mid-Term Recess) ****
       W 10/12       Topics - Black Holes, Stellar Oscillations          C6, C8

      ------------------------- Stellar Atmospheres -----------------------
       F 10/14       Basic Eqns, Radiative Transfer, Source Functions   C9, G7  

       M 10/17       Basic Eqns, Radiative Transfer, Source Functions   C9, G7  
       W 10/19       Solution to Radiative Transfer Equations           C10  
       F 10/21       Solution to Radiative Transfer Equations           C10  

       M 10/24      Solution to Radiative Transfer Equations            C10
       W 10/26       Excitation and Ionization, Atomic Physics          C11,G8
       F 10/28       Excitation and Ionization, Atomic Physics          C11,G8

       M 10/30       Excitation and Ionization, Atomic Physics          C11,G8
       W 11/2        Model Stellar Atmospheres                          C12,G9
       F 11/4        Model Stellar Atmospheres                          C12,G9
       F 11/4 [1-3:15 pm] In-Class Presentations (Interiors)

       M 11/7         *** ORAL EXAM #2 ***
       W 11/9        Continuum Observations                             G10
       F 11/11       Spectral Line Observation                          G12

       M 11/14       Line Shapes, Curves of Growth                      C14, G11
       W 11/16       Line Shapes, Curves of Growth                      C14, G11
       F 11/18       Line Shapes, Curves of Growth                      C14, G11

       M 11/21       Spectral Line Theory                               C13, G13
       W 11/23       Spectral Line Theory                               C13, G13
       F 11/25         **RECESS**

       M 11/28       Measuring Abundances                               G16
       W 11/30       Measuring Temperature, Radius, Pressure            G14, G15
       F 12/2        Measuring Turbulence and Rotation                  G17
        In-Class Presentations (Atmospheres)

        TBD:   Final Exam

CHAPTER: C:Collins; R: Rose G:Gray, BV:Bohm-Vitense volume 1

(This section is now required by the Rice Administration for all Syllabi)

Students completing this class should be able to do the following:

Disabled Students: Students with a documented disability that impacts their work in this class should contact me to discuss their needs. Disabled students should also register with the Disability Support Services Office in the Ley Student Center.